2018 ASHS Annual Conference

Hops (Humulus lupulus L.) have been gaining interests as a specialty crop for Florida’s rapidly growing craft beer industry. Although hops are adapted to temperate climates, previous studies demonstrated that some hop cultivars have potential for viable production even under Florida’s subtropical climate. Field experiments were conducted over the two seasons (2016–2017) to determine the optimal cultivar, planting material, nitrogen (N) fertilization rate, and in-row plant spacing for improving the establishment of hops in Florida. In the first season, rhizomes were planted in April on native, deep sand soil in a 6-m high trellis system. Treatments were factorial combinations of two cultivars (‘Cascade’ and ‘Chinook’), two nitrogen (N) rates (0.84 and 1.1 kg/ha/day), and three in-row plant distances (76, 91, and 107 cm). Harvests were performed 10 times between June 1 and Dec. 2, 2016. The maximal bine length was similar regardless of cultivars and other treatments (282 to 321 cm). By contrast, bine number recorded during the mid-harvest was 186% greater for ‘Cascade’ than ‘Chinook’ (4.1 vs. 1.4 bines/plant). Cone yield showed significant cultivar × N rate interaction effects: ‘Cascade’ increased yield with increasing N rate by 33% (333 vs. 442 kg/ha on a fresh-weight basis), whereas yield of ‘Chinook’ was very small regardless of N rates (40 kg/ha). In both cultivars, in-row plant spacing did not have significant effects on both bine growth and yield. Major drawbacks associated with rhizomes included low emergence rates (57% to 67%) and the infection of apple mosaic virus confirmed immediately after planting. Because of these drawbacks, the hop yard was reestablished using tissue culture seedlings of ‘Cascade’ in the second season. Compared with the plant growth in the first season, tissue culture plants had a relatively high survival rate (97%), but less vigorous growth with up to 176 cm in bine height and 3.7 in bine number. Cone yield was 322 kg/ha on a fresh-weight basis. The results suggest that ‘Cascade’ has a much higher yield potential than ‘Chinook’ in Florida, and that bine number is an important yield-related trait. Furthermore, the first season yield of ‘Cascade’ can be maximized by optimizing N fertilization rate. To establish a virus free ho yard with uniform stands, tissue culture seedlings are recommended than rhizomes.